He finished the race in in 1 hour, 48 minutes and 18 seconds—good for 4828th place.

It’s a good thing he finished back in the pack.

Shortly after crossing the finish line, Dr. Lao noticed a man had collapsed near the finish line.

"I took maybe two breaths and saw this man lying on the floor, and then I just ran over," Dr. Lao told ABC News affiliate KATU-TV. "I had to do it, he was unconscious, without a pulse and not breathing so if he was unattended for a few minutes that would have been very grave."

As paramedics arrived, Dr. Lao helped the man breathe again by opening his airway as paramedics shocked his heart. Soon after, the 43-year-old runner began to breathe again.